The present invention relates to a pixel structure, and in particular, to a pixel structure of an array substrate of a thin film transistor liquid crystal display (TFT-LCD).
In the current TFT-LCDs, electrostatic discharge (ESD) tends to occur at the intersection point between a gate line and a data line, resulting in a gate line-data line short defect (DGS defect).
FIG. 1A is a schematic view of a pixel structure manufactured by using a convent five-mask process, and FIG. 1B is a cross-sectional view taken along line A-A in FIG. 1A. Referring to FIG. 1A and FIG. 1B, the pixel structure comprises a pixel electrode 11, a data line 12, and a gate line 13, and the data line 12 and the gate line 13 intersect with each other to define a pixel unit. As shown in the layer structure in FIG. 1b, the data line 12 and the gate line 13 are disposed between a substrate 00 and a first protective layer (a passivation layer) 15. Through an active layer 123 at the intersection point, a parasitic capacitor is formed due to the data line 12 overlapping the gate line 13. DGS defect is prone to occur as a result of the electrostatic discharge of the parasitic capacitor.
FIG. 2A is a schematic view of a pixel structure manufactured using current four-mask process, and FIG. 2B is a cross-sectional view taken along line B-B in FIG. 2A. Referring to FIG. 2A and FIG. 2B, the pixel structure comprises a pixel electrode 22, a data line 22, and a gate line 23, and the data line 12 and the gate line 13 intersect with each other to define a pixel unit. As shown in the layer structure in FIG. 2b, the data line 22 and the gate line 23 are disposed between a substrate 00 and a second protective layer (a passivation layer) 25. Through an active layer 223 at the intersection point, a parasitic capacitor is formed due to the data line 22 overlapping the gate line 23. DGS defect is prone to occur as a result of the electrostatic discharge of the parasitic capacitor.
One of the disadvantages of the conventional pixel structure is lack of protection means for the parasitic capacitor that easily suffers from ESD, and it is difficult to repair after ESD occurs, reducing production quality and yield.